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Introduction to Radiation Protection Copyright © 2014 by Mosby, an imprint of Elsevier Inc. Use of Radiation in the Healing Arts Discovery of x-rays in 1895 Awareness of the value of x-rays to the medical community both as a diagnostic tool and as a...
Introduction to Radiation Protection Copyright © 2014 by Mosby, an imprint of Elsevier Inc. Use of Radiation in the Healing Arts Discovery of x-rays in 1895 Awareness of the value of x-rays to the medical community both as a diagnostic tool and as a therapeutic tool Awareness of both the beneficial and destructive potentials of x-rays Recognizing the ability of x-rays to cause injury in normal biologic tissue Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 2 What Are X-Rays? A form of ionizing radiation Ionizing radiation is radiation that produces positively and negatively charged particles (ions) when passing through matter. The production of these ions is the event that may cause injury in normal biologic tissue. and will X-rays is energy become ionized Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 3 Consequences of Ionization in Human Cells Atoms ↓ Molecule ↓ - Cell substance Tissue ↓ ↓ organ Stuff ↓ system yot Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 4 How Humans Can Safely Control the Use of “Radiant Energy” Use knowledge of radiation- induced hazards that have been gained over many years Employ effective methods to eliminate those hazards Control radiation produced from an x-ray tube and ensure safety during all medical radiation procedures Figure 01-01. Radiant energy is emitted from the x-ray tube in the form of waves (or particles). This manmade Limiting the energy deposited in energy can be controlled by the selection of equipment components and devices made for this purpose and by living tissue by radiation can the selection of appropriate technical exposure factors. reduce the potential for adverse effects. Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 5 Radiologic Technologists and Radiologists Are educated in the safe operation of radiation-producing equipment Use protective devices whenever possible Follow established procedures Select technical exposure factors that significantly reduce radiation exposure to patients and to themselves Benefit of these good practices Minimizing the possibility of causing damage to healthy biologic tissue Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 6 Effective Radiation Protection Ongoing responsibility of diagnostic imaging professionals to ensure radiation safety during all medical radiation procedures Obligation is fulfilled by adhering to an established radiation protection program Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 7 Radiation protection is for everyone Radiation Protection Effective measures employed by radiation workers to safeguard patients, personnel, and the general public from unnecessary exposure to ionizing radiation Unnecessary radiation Any radiation exposure that does not benefit a person in terms of diagnostic information obtained for the clinical management of medical needs Any radiation exposure that does not enhance the quality of the study Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 8 What Effective Protective Measures Take into Consideration Both human and environmental physical determinants Technical elements Procedural factors These measures consist of tools and techniques primarily designed to minimize radiation exposure while producing optimal- quality diagnostic images. Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 9 Concepts of Length, Time, Force, and Energy Units have been constructed to quantify every such concept uniquely. Three unit systems are currently in existence. Each one has a significant area of usage. For more information, see Appendix A in unit systems textbook. traditional 3 units in , cm si units meters standard units Time Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 10 Need to Safeguard Against Significant and Continuing Radiation Exposure Based on evidence of harmful biologic effects Damage to living tissue of animals and humans exposed to radiation Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 11 Radiation Exposure to the General Public Should always be kept at the lowest possible level Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 12 Justification and Responsibility for Imaging Procedures Benefit versus Risk Patient can elect to assume the relatively small risk of exposure to ionizing radiation To obtain essential diagnostic medical information when illness or injury occurs When a specific imaging procedure for health screening purposes is Figure 01-02. Mammography continues to be prudent the most effective tool for diagnosing breast cancer. It can be used as a screening tool or a Example: When women elect to diagnostic procedure. In either instance, the undergo screening mammography directly realized benefit, in terms of medical to detect breast cancer in its early information obtained, far outweighs any slight risk of possible biologic damage. (Frank ED, stages Long BW, Smith BS: Merrill’s Atlas of Radiographic Positioning & Procedures, ED 12, St. Louis, 2012, Mosby) Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 13 Accurate Diagnostic Efficacy How - are the X-rays The degree to which the diagnostic study accurately reveals the presence or absence of disease in the patient Maximized when essential images are produced under recommended radiation protection guidelines Provides the basis for determining whether an imaging procedure or practice is justified Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 14 Responsibility for Determining Medical Necessity of a Procedure for the Patient Referring physician Accepts basic responsibility for protecting the patient from radiation exposure that is not useful Relies on qualified imaging personnel who accept a portion of the responsibility for the patient’s welfare by providing high-quality imaging services Can only the DR in put orders Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 15 Responsibility for Determining Medical Necessity of a Procedure for the Patient (Cont.) Radiographer and participating radiologist Share in keeping the patient’s medical radiation exposure at the lowest possible level Help ensure that both occupational and nonoccupational doses remain well below allowable levels—that is, the upper boundary doses of ionizing radiation for which there is a negligible risk of bodily injury or genetic damage Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 16 Keeping Occupational and Nonoccupational Doses Well Below Maximum Allowable Levels Use the smallest radiation exposure that will produce useful images Produce optimal images with the first exposure Avoid repeat examinations made necessary by technical error or carelessness Figure 01-04. A, Posteroanterior chest projection requiring repeat examination because of multiple Examples of examination external foreign bodies (several necklaces and an that requires a repeat: underwire bra) that should have been removed before the x-ray examination. Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 17 As Low as Reasonably Achievable (ALARA) Principle An acronym for as low as reasonably achievable Synonymous with the term optimization for radiation protection (ORP) Intention behind these concepts of radiologic practice is to keep radiation exposure and consequent dose to the lowest possible level. * w/ Synonymous radiation optimization protection(ORP) Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 18 Cardinal Rules of Radiation Protection The three basic principles of radiation protection (STD) Time Distance Shielding These principles can be applied to the Patient Radiographer Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 19 Responsibility for Maintaining ALARA in the Medical Industry Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 20 Patient Protection and Patient Education Educating patients about imaging procedures helps to ensure the highest quality of service. Use appropriate and effective communication. Answer questions about the potential risk of radiation Figure 01-06. Effective communication is an important part of the exposure honestly. patient-radiographer relationship. Patients need to be educated Inform patients of what needs about imaging procedures so that they can understand what the procedure involves and what type of cooperation is required. to be done, if anything, as a The radiographer must answer patient questions about the potential risk of radiation exposure honestly. To create follow-up to their examination. understanding and reduce fear and anxiety for the patient, the radiographer can provide an example that compares the amount of radiation received for a specific procedure with natural background radiation received over a given period of time. (Radiobiology and Radiation Protection: Mosby’s Radiographic Instructional Series, St. Louis, 1999, Mosby) Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 21 Risk of Imaging Procedure versus Potential Benefit Risk (in general terms) The probability of injury, ailment, or death resulting from an activity Risk (in the medical industry) with reference to the radiation sciences The possibility of inducing a radiogenic cancer or genetic defect after irradiation (Radiation) Willingness to accept risk Perception that the potential benefit to be obtained is greater than the risk involved Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 22 Background Equivalent Radiation 10 Bert is the comparison Time (BERT) Pg. radiation of background Blue book A method that can be used to improve understanding and reduce fear and anxiety for the patient Compares the amount of radiation received with natural background radiation received over a given period of time (see Table 1-1 in textbook) Based on an annual U.S. population exposure of approximately 3 millisieverts per year Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 23 Advantages of the BERT Method When It Is Used Appropriately BERT does not imply radiation risk; it is simply a means for comparison. BERT emphasizes that radiation is an innate part of our environment. The answer given in terms of BERT is easy for the patient to comprehend. Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 24 Tools for Radiation Awareness and Community Education (TRACE) Program TRACE is a radiation dose awareness and dose reduction program for patients through the process of education for these individuals, for the community, for health care workers employed in the medical imaging profession, and for physicians. Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 25 TRACE Program (Cont.) Main components of the program include technologic enhancements such as Embedded software capable of recording and reporting dose Timely notification of the patient and the referring physician when the radiation dose is greater than 3 Gy Substantial lowering of CT doses through improved technology Alteration of existing protocols TRACE Program consists of two phases. End result of TRACE Program Reduction in dose to the patient Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 26 Standardized Dose Reporting Can lead to a reduction in dose for the patient Radiation dose to the patient for individual procedures, such as those involving general fluoroscopy, CT, and interventional procedures, needs to be dictated into every radiologic report. Benefit to the referring physician of having direct access to a patient’s radiation dose history: The option of knowing whether ordering an additional radiologic procedure is advisable Copyright © 2014 by Mosby, an imprint of Elsevier Inc. 27
